Substantial efforts are being made at present to utilize and/or re-process waste material for producing useful products of either gaseous or solid nature. The present invention is directed particularly to the utilization of cellulosic waste material for the production of useful gas such as methane and sometimes historically known as wood gas, details of which are set forth below.
Before the advent of substantial consumption of natural gas for both industrial and domestic purposes, so-called illuminating gas was manufactured for many years from coal and especially bituminous coal which was roasted in various types of similar equipment such as shown in prior U.S. Pat. No. 996,603 to Aslakson, dated July 4, 1911; U.S. Pat. No. 1,049,994 to Chapman, dated Jan. 7, 1913, and U.S. Pat. No. 1,107,917 to Derrick, dated Aug. 18, 1914. In general, these devices feed coal from a level below a generating chamber in the upper portion of which combustion takes place in a manner to produce gas which rises to discharge means in the upper portion of the chamber where the burning occurs. Air is delivered to the charge of coal in the chamber from a location either below or part way up the mass of coal being delivered to the combustion area of the chamber. In general, the burning of coal for this purpose occurred in a well insulated chamber in which refractory material lines a metal shell to protect the metal from destruction.
Another early U.S. Pat. No. 1,086,366, to Hirt, dated Feb. 10, 1914, showed a device in which set sawdust is delivered to a combustion zone in a retort lined with fire brick for purposes of providing heat as distinguished from a useful gas. In addition, prior U.S. Pat. No. 2,631,930 to Peters, dated Mar. 17, 1953, shows a system in which sawdust is carbonized by an electric heater coil and ash passes out the bottom of the heater chamber while the gas produced from the sawdust is filtered.
Another prior U.S. Pat. No. 3,977,947, to Pyle, dated Aug. 31, 1976, discloses a device in which a hot fluidized bed of previously formed charcoal has injected thereinto woody material to also carbonize it to form gas and charcoal, the gas being purified by a cyclone unit and a gas scrubber.
U.S. Pat. No. 4,019,444 to Kleeberg et al, dated Apr. 26, 1977, pertains to a system in which refuse is burned in an incinerator and the incinerator gases are treated for discharge to the atmosphere by being decontaminated in various units such as a cooler, electrostatic precipitator, gas scrubber, clarifier and the like.
Prior U.S. Pat. No. 4,052,173, to Schulz, dated Oct. 4, 1977, and U.S. Pat. No. 4,225,392 to Taylor, dated Sept. 30, 1980, show pyrolysis apparatus in which material is fed into the top of reaction chambers and, in the Schulz structure, gaseous fuels are produced by simultaneous gasification of coal and pyrolysis of organic solid waste material, while in Taylor, organic material is delivered to the chamber and heated air and gases cause destructive distillation of the carbohydrate material and the generation of carbon monoxide and carbohydrate gases.
Prior U.S. Pat. No. 4,086,144, to Grulich et al., dated Apr. 25, 1978, discloses a conical device adapted to process float tar in a coking process by separating the float tar and converting it in a manner so that it can be processed either separately or together with the bulk of curde tar discharged from the lower portion of the tar separator.
The apparatus comprising the present invention patentably distinguishes over the above-described prior art in various ways described in detail hereinafter, the advantages of which are also clearly set forth, as follows.